From a purely German/legal point of view, the fact that Quattro GmbH
has a "GmbH" (Gesellschaft mit beschraenkter Haftung) after the name means
that it is an independent, privately owned company. This is opposed
to Audi "AG" (Aktiengesellschaft), which means it is a publicly traded
company. Now, that doesn't mean that Audi doesn't own a part of Quattro
GmbH, which it may. BMW AG has the same sort of thing with BMW Motorsport
GmbH. Just FYI.
Jeff